Gun fire control system with hydraulic superelevation



April 23, 1957 R. E. BAUER ET AL GUN FIRE CONTROL SYSTEM WITH HYDRAULIC SUPERELEVATION Filed Feb. 25, 1955 2 Sheets-Sheet 1 \\m NMW R. E. BAUER Erm. 2,789,475

2 Sheets-Sheet 2 April 23, 1957 GUN FIRE: CONTROL SYSTEM wITR HYDRAULIC SUPERELI-:VATION Filed Feb. 25. 1955 United States Patent O GUN FIRE CONTROL SYSTEM WITH HYDRAULIC SUPERELEVATION Russell E. Bauer, Grosse Pointe Woods, and John D. Lorimer, Birmingham, Mich.

Application February 25, 1955, Serial No. 490,550

3 Claims. (Cl. 89-41) The present invention relates generally to the control of hydraulic systems and particularly to the micro control of hydraulic circuits by the precise volume displacement of extremely small amounts of hydraulic fluid. Most specifically, the invention relates to apparatus for supplying small amounts of hydraulic fluid to a gun elevating cylinder for the purpose of accurately applying super-elevation to the gun to obtain a properly arched trajectory when firing the gun at the longer ranges.

In many hydraulically-controlled devices, it frequently becomes necessary to control the amount of hydraulic Huid delivered to a Huid-actuated device with great precision-i. e., with precision beyond the capacity of the various on-otf or throttling types of valves. The gun of a military tank is one such instance. Such a gun is elevated and depressed by a double-acting hydraulic cylnder and piston assembly. The action of such cylinder can be controlled, for example, by a control system such as that disclosed in the copending application of Russell E. Bauer, S. N. 330,871, led January 12, 1953, or by other means. The hydraulic control system is used with a gunsight which includes an optical sterioscopic range inder coupled to an automatic superelevation computer which translates the range determined by the range finder into a super-elevation angle (taking into account the type of shell being fired). Since in many combat situations the typical high velocity tank gun must be sighted visually like a rifle, the flat trajectory over the shorter ranges making this possible, it has been necessary to have the line of sight of the gunsight locked in parallelism with the bore of the gun by means of a ballistic drive linkage. When such a gun is to be fired over longer ranges with an arched trajectory, however, the bore of the gun must necessarily be above the line of sight and it would be impossible to keep a locked gunsight on target. Heretofore, it has been the practice to automatically apply the super-elevation angle to the ballistic drive to cause the sight to be depressed from the target. The gunner then elevates the gun to relay the sight on target, this operation involving a short delay which might give an adversary tank the opportunity for the rst shot. The super-elevation angle as used herein is the actual angle between the line of sight through the gunsight (when on target) and the bore of the gun also when the latter is elevated to hit target. The elevation angle of the gun, on the other hand, has reference to ground level and is not involved in sighting the gun since the tank itself may be on a fore-to-back incline or the target may be above or below the tank. It can be appreciated that the line of sight, therefore, is not always horizontal. The device of this invention makes it possible to lock a gunsight in parallelism with the gun bore at the shorter point blank ranges and to apply the super-elevation to the gun to move its bore out of parallelism with the gunsight at the longer ranges while the latter stays on target. In most instances, the super-elevation angle is not large, it usually varies from a fraction of ardegree to 4 or 5 2,789,475 Patented Apr. 23, 1957 degrees, or slightly more. lt has been very difiicult, heretofore, to control the gun elevating cylinder with sufficient precision to make such ne adjustments in superelevation angle.

lt is an object of this invention, therefore, to provide a control device capable of accurately displacing and delivering extremely minute quantities of hydraulic uid.

Another object of this invention is to provide a superelevating device for a hydraulically-controlled gun.

Still another object of this invention is to provide a hydraulic displacement-type control valve which will accurately deliver hydraulic oil or fluid in response to the turning of a micrometer advance screw.

Yet another object of this invention is to provide a control valve of the type described which will permit the full travel of the screw with pressure of and without displacing oil.

Still other objects and advantages of the present invention will be apparent, or will become apparent, in the following more detailed description of the invention when taken in conjunction with the accompanying drawings, in which:

Fig. 1 is a schematic representation of a tank gun, its hydraulic elevating cylinder, a gunsight, and a gunsight computer, and showing especially the use made of the hydraulic control device of this invention;

Fig. 2 is a longitudinal section through the center of control device of this invention; and

Fig. 3 is a plan view of the hydraulic control device of this invention.

In accordance with the present invention, a hydraulic control device or valve is provided which comprises a micrometer screw-Operated spool-type valve arranged to control the admission of operating fluid to a hydraulic delivery cylinder and piston assembly, the movement of the delivery piston serving to displace hydraulic fluid to a fluid-actuated device. Also, in accordance with the present invention a micrometer screw advance means attached to the spool valve of the control device is utilized to control the movement Aof the spool with great precision. In a tank gun control the micrometer advance screw is mechanically connected to the super-elevation computer in order to automatically apply super-elevation to the controlled gun in order to accurately place the projectile at the longer ranges yet enable the gunsight (which is also coupled to the gun) to stay on target.

As will be seen in Fig. l, the hydraulic control device 10 of this invention is connected by means of a shaft, for example a exible shaft 11 to a super-elevation computer 12. The computer 12 has internal gearing which operates a shaft 13 which is shown extended upwardly for connection to a ballistic drive connection indicated generally by the numeral 14. The computer is connected to a gunsight 1S by means of a second flexible shaft 16. After line of sight is adjusted on target the tank commander looks through the gunsight 15 and turns the handle 17 to compute range. The revolutions of wheel 17' indicating range are transmitted to the computer 12 by means of the shaft 16 to feed range into the latter. The computer in turn, by means of a motor and internal gearing, computes the correct super-elevation angle and translates the latter into rotary motion of a shaft (not shown) journalled in fitting 18 and connected by gearing to shafts 11 and 13. The computer 12 has a manual handle 19 in case of failure of the tank electrical system, the gunner reading the range 0n the inner scale of dial 20 and turning the handle 19 until the outer dial coincides, thus turning shafts 11, 13. The rotary motion of shaft 11 in either case causes control device 10 to deliver oil through either of lines 21, 22 and lock valve 42 to operate a gun elevating cylinder 23 which causes the tank gun 24 to be elevated or depressed accordingly.

The gunsight is connected to the gun 24 by a pair or parallelogram linkages, one indicated generally by the numeral 2S being connected on one end to the gun trunnion 26 and ,on the other end to a ballistic drive 14, and the other indicated by the numeral 28 connecting the ballistic drive 14 with the sight 15. Movement of the gun is transmitted through linkages 25, 28 of the gunsight so that the latter always follows the former and the line of sight is parallel to the bore of the gun. The shaft 13, however, is connected between the linkages in such a manner that the gunsight 15 does not remain parallel with the gun (in other words, stays on target) at the longer ranges. This is brought about by mounting the shaft 13 in arm 29 attached to linkage 25 and providing a screw end fitting 30 on the shaft end which engages a nut assembly 31 in arm 32 of linkage 28. Thus, when super-elevation is applied to or withdrawn from the gun, the barrel elevates or depresses causing corresponding movements in linkage 25. At the same time, however, the shaft 13 is turned to advance or retract the screw 30 by a corresponding amount thereby causing the linkage 28 to remain stationary. When no super-elevation is applied by the computer the sight and the bore of gun 24 are locked in parallelism by the linkages 25, 28.

High pressure operating oil or fluid is supplied to the valve 10 through line 40, delivery of or return of oil to the device being accomplished through lines `21 and 22, and low pressure exhaust fluid being returned to the pump or reservoir through line 38. When the system is first filled with uid, air is liable to collect in the cylinder 54 causing Variable displacement of oil. As shown in Fig. 2, bleeder valves 33 can be provided on either side of the piston to remove the entrapped air.

The hydraulic control device 10 of this invention is shown in greater detail in Figs. 2 and 3. The device comprises a somewhat elongated body portion 50 having a head portion 52 to which is attached a cylinder housing 54. The head portion 52 has a peripheral groove 56 in which is disposed a circular O-ring sealer element 58 to elect a seal between head 52 and cylinder 54, the cylinder 54 being secured to head 52 by means of a collar 60 and a plurality of stud bolts 62. The collar 60 clamps the end of the cylinder over a snap retainer ring 64 contained in a peripheral groove 66 in cylinder 54. Cylinder 54 is closed and sealed by an end plate 68 which has an O-ring sealing element 70, a snap ring 72 and an outer collar 74 which is clamped to end plate 68 by means of bolts 76. A hydraulic fitting 78 having an O-,ring seal 80 is provided in end plate 68 to serve as the hydraulic iiuid delivery Or return port (the delivery line 21 of Fig. l being connected to fitting 78).

Inside the bore of body portion 50 there is disposed a sleeve 90 and inside of the latter there is slidably disposed a valve spool 92. The sleeve 90 is slidably supported in body 50 on a plurality of lands 94 disposed along its length and having O-ring seals 96 in the groovelike peripheral slots 98 between the lands. An atmospheric Vent passageway 97 is provided between the sealer elements in the bore to keep the seals 96 seated against one side of their slots so they will not shift and displace oil or cause variable displacement of oil. A passageway 100 is bored transversely through sleeve 90 for admitting hydraulic uid from the spool to the sleeve side of cylinder 54, a passageway 102 for conducting high pressure fluid to the spool 92, and a passageway 104 for escape of exhaust or low pressure uid. On the outer end of sleeve 90 in the cylinder 54 there is secured a piston 106, the piston 106 being secured to sleeve 90 by means of a retainer ring 108 and a retainer plate 110. Flat headed screws 112 secure retainer plate 110 to piston 106. The escape of hydraulic uid along sleeve 90 through piston 106 is prevented by means of an O-ring seal 114 and by means of a second O-ring seal 116 located between retainer plate and piston 106. By-passing of high pressure operating hydraulic uid around piston 106 is prevented by means ot O-ring seals 118 in grooves 120 in the outer circumference of the piston. An atmospheric vent passageway 122 in piston 106 is located between O-ring seals 118 to insure their seating against one side of their grooves. Likewise, vent passageway 123 is provided in head 52 to insure stationary seating of O-ring 58 in its groove. Passageway 122 is connected to the low pressure exhaust passageway in the spool through a sleeve passageway 124.

The spool 92 has a land 130 on its end adjacent cylinder 54 to cooperate with and close off passageway 100, and a land 132 on its outer end to cooperate with and close off passageway 104. Passageway 102 in sleeve 90 is always open to the exterior of the spool so that the pressure exerted on lands 130, 132, when the latter are in the closed position, always balance each other. Down the longitudinal `center of spool `92 there is provided a central passageway 134 having an enlarged portion 136 near the cylinder end which communicates with an enlarged central bore 138 of the sleeve 90. In the enlarged spool center bore 136 is a spool guide pin 140 which has its length therein enclosed in a compression spring 142- which serves to return spool 90 to the closed position when the spool micro adjusting screw 144 is retracted. Pin 140 has an enlarged head 141 nested in a V-shaped depression in retainer plate 112. Spring 142 also provides a certain amount of resistance towards leftward movement of spool and keeps the spool 92 lin engagement with an advance screw 144 thereby securing smooth positive action of the spool.

The micro-adjusting screw 144 has threads only on its outer end 146 and is restrained from turning in sleeve 90 by means of a pin 148. The outer end of screw 144 is engaged yby a nut 150 so that rotation of nut 150 will adavnce and retract the screw 144 and thus effect movement of spool 92 relative to sleeve 90.

The nut or screw advance tting 150 is designed to have its outer end connected to the flexible shaft 11, and has 4internal threads in its end bore 156 which engage the threaded end 146 of advance screw 144. The nut 150 is supported in body 50 in a double row of ball bearings 158 and secured therein by means of an annular outer cover 160 which is sealed by means of a gasket 162 and held in position by screws 164.

The control device is shown in Figs. 2 and 3 in one of its operative positions with the piston 106 near the head 52. It is to be understood that the piston can move in both directions. As shown, the spool is in the closed or centered position. In operation, Athe nut 150 is rotated by shaft 11 so as to move screw 144 to the left. When this is done, the screw 144 moves spool 92 to the left until the trailing edge of land 130 clears the leading edge of passageway 100. High pressure hydraulic fluid then liows into the valve through line 40, thence through passageway 102, down the length of the outer surface of spool 92 and from thence through passageway 100 to the space behind piston 106. The piston 106 is thereby caused to move to the left displacing oil in space 182 and delivering it through fitting 78 to line 21 and from thence to cylinder 23. Simultaneously, fluid is exhausted from the opposite end of cylinder 23 through line 22. The initial leftward movement of spool 92 also causes the trailing or outer edge of land 132 to open passageway 104 to allow the escape -of uid from line 22 along the outer surface of screw 144 and out through line 38 to the reservoir. This same leftward movement of piston 106 also causes sleeve 90 to move thereby causing land 130 to again close passageway 100 and land 132 to move over port 104. In the latter position oil will not ow into or out of the valve.

Removal or reduction of super-elevation angle 1s brought about by the computer reversing shaft 11 and retracting thev advance screw 144. The 4spring 142 then urges the spool to the right to cause the'trailing edge of land 132 to connect passageway 104 with passageway 102 to cause high pressure tluid to be discharged through line 22 to the down end lof cylinder 23. Movement of the spool to the right simultaneously causes the trailing edge of land 130 to open passageway 100 establishing a connection between space 180 and line 38 through passageways 100, 138, 136, 134 and around the screw 144 which is forked. Flow of oil into the down side of 'cylinder 24 causes a like amount of oil to be expelled from the up end, this oil being delivered through line 21'to space 182 causing the piston 106 to move to the right expelling a similar quantity of oil from space 180 through line 38 to drain. The movement of piston 106 moves the sleeve 90 to the right causing lands 130, 132 to again close, respectively, sleeve passageways 100, 104. The sleeve and spool will always regain their balanced, closed position in this manner after the required amount of uid has been expelled from, or returned to, spaces 180, 182 of cylinder 54. Because the spool and sleeve are always balanced, relative movement between them is effected only by the advance screw 144 and the compression spring 4142. The sleeve 9i), however, is entirely free to move, except for the small resistance spring 142, relative to spool 92 in response -to piston movements caused by admission of fluid to spaces 180, 182. The O-ring seals provide ecient high pressure seals, especially between the outer sleeve diameter and the internal bore surface. The spool, however, should be accurately fitted inside the sleeve by a lapping operation. It also should be appreciated that the screw 144 may be moved the full length of its travel, when the oil pressure is off, without displacing oil. When the pressure is restored the sleeve and spool will recenter themselves very quickly to establish the correct displacement condition as dictated by the then-existing position of the spool. As shown in Figs. 2 and 3, the sleeve and spool are somewhat elongated, the length of these elements being determined by the length of travel desired in the screw. When the installation does not require this long length of travel during the power-olf period, the spool and sleeve can be made much shorter.

The control device of this invention is capable of controlling hydraulically-operated devices other than a gun cylinder with great precision. For example, automatic gear cutting and finishing machines have some of -their operating mechanisms such as infeed and sidefeed slides controlled hydraulically. The displacement valve of this invention can be employed to operate these slide mechanisms With great accuracy within the extremely small tolerances allowed in the cutting and finishing of gears. Still other applications will readily occur to one skilled in the art.

What is claimed is:

l. In a lire control system for a tank gun the combination comprising an hydraulic load cylinder and a piston movable therein connected to said gun for elevating and depressing the same, a gunsight, a super-elevation computer having means for computing a superelevation angle and producing a movement output proportional thereto, said computer being operatively connected to said gunsight independently of the gun, a pair of interconnected parallelogram linkages operatively connecting said gunsight to said gun so that the line of sight through said gunsight is normally parallel to the bore of the gun at the shorter ranges, a pair of shafts arranged to be rotated independently as a function of said movement output by said computer, one said shaft being operatively connected to one of said linkages to actuate said gunsight to vary the relative elevational positions of said gunsight and said gun, a super-elevation displacement control valve adapted to be hydraulically connected to a source of fluid under pressure and having a micrometer operating screw operatively connected to the other of said computer shafts, a fixed control cylinder, a control piston movably disposed in said control cylinder, aA xed `cylindrical body portion connected to said control cylinder and aligned axially therewith, a sleeve fixed to said control piston slideably disposed in said body portion extending into said control cylinder and having three radial ports therein, a valve spool slideably disposed in said sleeve and having a pair of lands slideably supporting it in said sleeve, said body portion having three annular recesses formed in its inner surfaces which may be 'selectively brought into alignment by Way of said ports upon axial movement of said spool, a first of said recesses during use being connected to the pressure side of said source, `a second set of said recesses during use being connected to the drain side of said source, a third of said recesses being connected to one end of said load cylinder, hydraulic means connecting the other end of said load cylinder to one end of said control cylinder, the other end of sai-d control cylinder being selectively connectable to said first and second recesses upon axial displacement ofsaid spool, said spool being adapted to be axially displaced in opposite directions upon rotation of said other computer shaft as a function of said movement output whereby said load piston is actuated as a function of the displacement of said spool, said one shaft connected to said one linkage being arranged to actuate said gunsight according to the rotation of said one shaft so as to cancel out the movement output applied through said other computer shaft to said load cylinder whereby to move said gun out of parallelism with said gunsight at the longer ranges while thegunsight stays on target.

2. Ina firecontrol system for a tank gun the combination comprising an elevating mechanism having -a load cylinder and a piston movable therein adapted for connection to said gun for elevating and depressing the same, a gunsight, a superelevation computer having means for computing a superelevation angle at the longer ranges and producing a movement output proportional thereto, said computer being operatively connected to said gunsight, ballistic means operatively connecting said gunsight to said gun so that the line of sight through said gunsight is normally parallel to the bore of the gun at the shorter ranges, first and second means independently moved simultaneously by said computer, said first independently movable means being operatively connected to said ballistic means, a displacement control valve adapted to be connected to a source of ud under pressure having a control cylinder and an attached axially aligned cylindrical body portion, a control piston movable in said control cylinder, a sleeve fixed to said control piston extending into said control cylinder and having three radial ports therein, a cylindrical valve spool having a pair of lands slideably supporting it in said sleeve and a central passageway therethrough, said body portion having three annular recesses formed in its inner surface which may be selectively brought into alignment by way of said ports upon displacement of said spool, a first of said recesses during use being connected to the pressure side of said source, a second of said recesses during use being connected to the ldrain side of said source, a third of said recesses being connected to one end of said load cylinder, hydraulic conduit means connecting the other end of said load cylinder to one end of said control cylinder, the other end of said control cylinder being selectively connectable through one of said ports with said first and second recesses upon axial displacement of said spool, valve spool operating means connected to said second independently movable means to axially displace said spool as a function of said movement output thereby actuating said load piston as a function of the displacement of said spool, said first independently movable means being arranged to actuate said ballistic means to elevate and de press said gunsight as a function of said movement output so as to cancel out the movement output applied to said load piston through said second independently movable means whereby to move said gun out of parallelism with saidgunsight at the longer ranges while sa-id gunsight stays on target.

3. In a tire control system for a tank gun the combination comprising an hydraulic load elevating mechanism having a load cylinder and a piston movable therein adapted for -connection to said gun for actuation thereof, an hydraulic displacement control device adapted to lbe hydraulically connected to a source of uid under pres sure having a fixed housing divided into a bore portion and connecting therewith an axially aligned control cylinder, a control piston movably disposed in said control cylinder, a sleeve fixed to said piston slideably disposed in said bore portion extending into said control cylinder having three radial ports therein, a cylindrical valve spool having a pair of lands slideably supporting it in said sleeve and a central passageway therein, said bore portion having three annular recesses formed in its inner surfaces which may be selectively brought into alignment by way lof said ports upon axial displacement of said spool, means for connecting a tirst of said recesses on the one side thereof during use to the pressure side of said source, means for connecting a second of said recesses on one side thereof during use to the drain side of said source, means connecting a third of said recesses on the one side thereof to one end of said load cylinder, hydraulic conduit means connecting the other end ot said load cylinder to one end of said control cylinder, a rst and second of said ports positioned to be closed respectively by one and another of said lands, means for displacing said spool in opposite directions independently of said control piston, the other end of said control cylindei-*being selectively connectable upon axial displacement of said spool through said first port with (l) said rst recess on the other side thereof through the third of said ports, and (2) with the second of said recesses on the other side thereof through said central passageway in said spool, the other side of the second of said recesses being connectable with said third recess on the other side thereof through said second port upon axial displacement of said yvalve spool, and the other side of the rst of said recesses being connectable with said third recess on the other side thereof through said second and third ports upon axial displacement of said valve spool, whereby movement of said load piston in a selected direction is accomplished as a function of the displacement of said spool.

References Cited in the file of this patentl UNITED STATES PATENTS 2,258,464 Moody Oct. 7, 1941 2,261,444 Neubert Nov. 4, 1941 2,363,179 Harrington Nov. 2l, 1944 2,498,810 Huber Feb. 28, 1956 2,586,280 Wiedmann Feb. 19, 1952 2,607,321 Lado Aug. 19, 1952 2,640,466 Feeney June 2, 1953 2,667,146 Wheeler Ian. 26, 1954 2,696,144 Herlach Dec. 7, 1954 FOREIGN PATENTS 773,936 France Sept. 10, 1934 

